1. Field of the Invention
The present invention relates generally to methods for fabricating magnetic heads, and more particularly to methods for notching the P1 magnetic pole of such magnetic heads.
2. Description of the Prior Art
One approach to increasing the areal data storage density of magnetic disks is to narrow the width of the data tracks written on the disks, such that more tracks per inch can be written, and therefore more data stored on the disk in a given area. However, it is also necessary to provide some spacing between adjacent tracks, and the spacing required between data tracks is a function of the strength of the fringing magnetic fields that are created by the magnetic head. Such fringing fields induce unwanted side writing from the magnetic head. Generally, the width of the base of the P2 magnetic pole tip determines the width of the written data track. As the width of the base of the P2 pole has been reduced, in order to produce narrower track widths, the effect of side writing has become more pronounced in relation to the narrowed track widths. Therefore, it is desirable to minimize the fringing fields generated by magnetic heads, such that adjacent data tracks can be written more closely together, and the areal data storage density on the disk thereby increased.
One of the fabrication methods that has been undertaken in the prior art to reduce the fringing fields is to notch the P1 magnetic pole, as is known to those skilled in the art. Such P1 pole notching can substantially reduce the fringing magnetic fields generated by the magnetic head, and can thereby ultimately increase the areal data storage density on the disk. The standard P1 notching process of the prior art utilizes the previously fabricated P2 pole tip as an etching mask element in the notching process, and the process includes first etching through the write gap layer, typically alumina (Al2O3), and then etching into the P1 pole layer (typically Permalloy, a NiFe compound). A problem that initially exists in the prior art P1 notching process that utilizes an argon ion beam is that the alumina write gap layer is significantly more resistant to etching by the argon ion beam than the NiFe material of the P2 pole tip and the P1 layer. Therefore, where an argon ion beam was used in the prior art to conduct the P1 notching step, significant portions of the P2 pole tip were etched away while the beam more slowly etched through the alumina write gap layer. Thereafter, further portions of the P2 pole tip were etched away while the P1 pole was subsequently notched by the ion beam. As a result, the earlier prior art P1 pole notching process required the initial fabrication of a rather thick and wide P2 pole tip, such that a properly sized P2 pole tip remained following the etching in the P1 notching step utilizing an argon ion beam.
With the continuing emphasis on increasing the data areal data storage density, further refinements in the P1 pole notching process are required to reduce side writing from the magnetic head. The magnetic head of the present invention with its improved P1 pole notching method provides such a side writing reduction.